This invention relates to high speed centrifugal compressors and more particularly to a high speed centrifugal compressor driven by a gas turbine. Centrifugal compressors find applications in various fields and increasing utility in the expanding natural gas industry for such services as gas gathering, boosting, transmission, repressuring and distribution, and the like. In the gas boosting area particularly, there is a need for high speed centrifugal compressors which will operate relatively maintenance free, are compact for ease of transportation and installation on site and which are driven by prime movers which us readily available energy sources. Thus, it would be desirable in the natural gas industry, as well as in the process industry, to have available a high-speed compressor which together with its prime mover provides compact, efficient, comparatively maintenance free operation.
Previously, centrifugal compressors have only been able to operate at high shaft speeds through the use of gear trains interposed between the compressor and the prime mover. However, the use of gear trains not only requires operation supervision, because of lubrication requirements and the like, but may also give rise to maintenance problems typically associated with the presence of moving parts which are subject to wear and breakdown. In addition, the presence of a gear train increases the size and weight of the overall compressor-prime mover unit. While gas turbine engines are capable of delivering high horse power in a compact unit and can provide high shaft speed, their use to drive centrifugal compressors has heretofore not been entirely satisfactory. In particular, the use of turbine engines to drive compressors has led to disadvantages arising from problems of mechanical alignment due to the mechanical coupling between the compressor shaft and the turbine engine power output shaft. These mechanical alignment problems are compounded where the turbine engine has mechanically connected gas compressor and power turbine stages.
Due to the aforementioned drawbacks, there has not previously been available a combined high speed centrifugal compressor-prime mover unit which is both compact and efficient in operation as well as free from alignment and maintenance problems so as to be suitable for process and natural gas industry uses including uses as diverse as offshore platform gas operations.